Want to win a PS4? Go Premium and enter to win our High-Tech Treats giveaway. Enter to Win

x
?
Solved

AIX RamSan 2

Posted on 2014-01-29
2
Medium Priority
?
701 Views
Last Modified: 2014-02-07
this is 2nd part of the below Q

http://www.experts-exchange.com/OS/Unix/Q_28349015.html

IBM is talking about "ACA"
==================
Is that an sdd or aix setting (ACA)?

ramsan had it enabled by default.

what is your input here?
0
Comment
Question by:it-rex
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
2 Comments
 
LVL 68

Accepted Solution

by:
woolmilkporc earned 2000 total points
ID: 39819433
Do you mean "Auto Contingent Allegiance"?

That's a form of exception condition handling, exception recovery  and related message passing in the scsi protocol.

ACA is set when a "Check Condition" status occurs
ACA remains in effect until the initiator sends "Clear ACA"
During ACA only certain commands are allowed, marked by the ACA queue tag.

ACA (and CA, ECA which work a bit differently) are firmware driven.

AIX needs ACA being set to enable concurrent command processing. This is because ACA in a way disconnects the exception handling from command processing (a concurrent command can execute if allowed by the ACA queue tag before the recovery procedure for another command has completed).

Afaik on the Flash you can configure ACA on a per LUN basis, which specifies whether to handle check conditions on that LUN following the ACA method.
Again: For AIX, ACA is mandatory. It's not "settable", neither in AIX nor SDD.

On the DS8K, ACA is set by choosing the appropriate "hosttype" for the specific volgrp.

AIX had a problem with MPIO round robin and ACA, because it could happen that multiple "clear ACA" commands were sent, which could affect performance.
AIX 7.1 TL2 SP1 should have this problem fixed, though.


wmp
0
 
LVL 11

Author Closing Comment

by:it-rex
ID: 39842930
thanks
0

Featured Post

Free Tool: IP Lookup

Get more info about an IP address or domain name, such as organization, abuse contacts and geolocation.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This tech tip describes how to install the Solaris Operating System from a tape backup that was created using the Solaris flash archive utility. I have used this procedure on the Solaris 8 and 9 OS, and it shoudl also work well on the Solaris 10 rel…
I promised to write further about my project, and here I am.  First, I needed to setup the Primary Server.  You can read how in this article: Setup FreeBSD Server with full HDD encryption (http://www.experts-exchange.com/OS/Unix/BSD/FreeBSD/A_3660-S…
Learn how to get help with Linux/Unix bash shell commands. Use help to read help documents for built in bash shell commands.: Use man to interface with the online reference manuals for shell commands.: Use man to search man pages for unknown command…
In a previous video, we went over how to export a DynamoDB table into Amazon S3.  In this video, we show how to load the export from S3 into a DynamoDB table.
Suggested Courses

604 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question